16 Questions
What is the purpose of the housing in a fluid coupling?
To contain the fluid and turbines with an oil-tight seal
What is the direction of the fluid motion in a fluid coupling when the input and output stages have identical angular velocities?
Circular and co-axial with the axis of rotation
What is the function of the pump or impellor in a fluid coupling?
To impart linear and rotational motion to the fluid
What happens to the fluid motion in a fluid coupling when there is a difference between input and output angular velocities?
The fluid motion becomes toroidal with a circular component
What is the typical source of power for the prime mover in a fluid coupling?
Electric motor or internal combustion engine
What is the function of the output turbine or driven member in a fluid coupling?
To cause a torque due to the difference in angular velocities
What is the shape of the path of the fluid motion in a fluid coupling?
Toroidal
What is the purpose of using a fluid coupling in an automobile transmission?
To transmit power from the engine to the gearbox
What is the primary function of a transmission system in a vehicle?
To provide high torque at the time of starting, hill climbing, and accelerating
What is the purpose of a free wheeling mechanism in a transmission system?
To disconnect the engine and the road wheels
What is the difference between a sliding mesh gear box and a constant mesh gear box?
The way the gears engage and disengage
What is the purpose of a torque converter in an automatic transmission system?
To convert mechanical energy into hydraulic energy
What is the main advantage of an epicyclic gear box in an automatic transmission system?
It is compact and lightweight
What is the purpose of a fluid coupling or hydraulic coupling in a transmission system?
To transmit rotating mechanical power
What is the main difference between a manual transmission and an automatic transmission?
The driver's involvement in gear shifting
What is the purpose of a planetary gear system in a transmission system?
To provide a variable torque output
Study Notes
Transmission System (Gear Box)
Necessity for Gear Ratios
- Gear box provides gear ratios in transmission to control speed
- Synchronous gear boxes, 3, 4, and 5 speed gear boxes are examples
- Free Wheeling mechanism, Planetary gear systems, overdrives, fluid coupling, and torque converters are used
Automotive Gears
- Gears play an important role in controlling speed in vehicles
- Types of gears: ring and pinion, spiral gear, hypoid gear, hydraulic gears, reduction gearbox
- Gear size varies depending on vehicle size
- Low gears cover shorter distances and are useful at low speeds
- High gears have a larger number of teeth
Functions of Transmission
- Provides high torque at starting, hill climbing, accelerating, and pulling a load
- Permits engine crankshaft to revolve at high speed while wheels turn at slower speeds
- Provides variable torque through a set of gears
- Allows changing vehicle speed while keeping engine speed the same (within a certain limit)
- Provides a neutral position to disconnect engine and road wheels
- Enables backing the car by reversing the direction of rotation of the drive
Necessity of Transmission
- Variation of resistance to vehicle motion at various speeds
- Variation of tractive effort of the vehicle available at various speeds
Types of Transmission
Manual Transmission
- Sliding Mesh Gear box
- Constant Mesh Gear box
- Synchromesh Gear box
Automatic Transmission
- Overdrive (semi-automatic)
- Fluid drive or Fluid coupling
- Fully automatic
- Epicyclic gear box
- Free Wheeling unit
- Torque Convertor
Fluid Coupling or Torque Convertor
- Hydrodynamic device used to transmit rotating mechanical power
- Alternative to a mechanical clutch in automobile transmission
- Consists of:
- Housing (shell) containing the fluid and turbines
- Two turbines: pump (input shaft) and turbine (output shaft)
- Hydraulic fluid
- Working principle:
- Input shaft rotates the pump, imparting linear and rotational motion to the fluid
- Fluid is directed towards the output turbine, causing a torque and rotation
- Motion of the fluid is toroidal, with a circular component when input and output angular velocities differ
This quiz covers the basics of transmission systems, including gear boxes, gear ratios, and other mechanisms used in automotive vehicles. Learn about the different types of gear boxes and their applications.
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